The characteristics of (6,7-dimethyl-8-ribityl) lumazine proteins isolated from the marine bioluminescent bacteria Photobacterium phosphoreum and P. leiognathi, will be determined. The primary structure of each of these proteins will be determined using classical methods. Fast preparative HPLC methods will be developed to purify these proteins together with the luciferases from Photobacterium and bioluminescent Vibrios. Spectroscopic techniques using a Picosecond Photon Counting Spectrometer will be employed to measure the parameters of the association of lumazine protein and its ligand, and the lumazine protein-luciferase associations. Other ligands will be attached to lumazine protein instead of the lumazine derivative and these artificial proteins will be examined for their fluorescence and bioluminescence properties. Energy transfer techniques will be used to describe the topological features of the protein-protein complexes. A search will be made for lumazine proteins in bioluminescent Vibrios as well as in other non-bioluminescent procaryotes. 6,7-dimethyl-8-ribityllumazine is an intermediary metabolite in Vitamin B2 biosynthesis and study of its binding to proteins may lead to the finding of new types of broad spectrum antibiotics.